5.56mm Cartridge History
The 5.56mm cartridge was designed by Robert Hutton, then technical editor of Guns & Ammo magazine and owner of a California range. He responded to Army requirements for a round for the AR-15 whose projectile would exceed Mach 1 at 500 meters, a high standard for that time. Hutton teamed with Gene Stoner of Armalite to produce the winning design, a .222 with a longer case and 55 grain Sierra boat tail bullet. [See Guns & Ammo Annual for 1971].
The M193 round has been an effective military cartridge that met its design expectations. It is shorter range but just as lethal as the Cal. .30 and 7.62 rifle rounds it replaced while its much lighter weight gave soldiers the opportunity to carry many more rounds into the battle. Recently the 5.56 x 45mm M193 has been improved by adoption of the NATO approved SS109, developed by FN (Fabrique Nationale) of Belgium, that differs primarily in that the bullet is heavier.
Packaging the 5.56mm Military Ammunition
U.S. military packaging of the 5.56mm ammunition is in two forms, one for the M16 family of rifles which uses 10 round stripper clips and the other in link belts for the M249 SAW machine gun.
When packaged for the rifles, three ten round clips will be inserted into a point protector paperboad carton and then four cartons will be packed in a 4 pocket bandoleer, for a total of 120 rounds per bandoleer. Seven such bandoleers will be packed into an M2A1 ammo can (NSN 8140-00-960-1699, holds 840 rounds) and two M2A1s will be packed together in a wirebound wooden crate (1680 rounds) as in the top photo on this page. The crates are shipped 48 to a pallet.
Prior to the four pocket bandoleers, there were 6 and 7 pocket bandoleers, typical in Vietnam. With those, there were two stripper clips in a cardboard sleeve in each pocket, for a total of 6x20=120 or 7x20=140 rounds per bandoleer. There were then 840/120=7 or 840/140=6 bandoleers per ammo can, always a total of 840 rounds per can. With each bandoleer, there was a metal magazine guide for speed loading the stripper clips into either 20 or 30 round magazines. The photo to the right shows the markings on a six pocket bandoleer.
For training purposes the military has been experimenting with fiberboard boxes for the 5.56mm ammo to save on the cost of delivering ammo cans, bandoleers and other disposable packaging. Mission packaging is not changed, bandoleers and ammo cans will still be used.
Linked 5.56mm ammo came in 200 round magazines for the M249 SAW packed into 800 cartridge PA-108 'Fat 50' Ammunition Cans. Belts typically had 4 M855 ball and 1 M856 tracer in repeating pattern connected with M27 steel links.
Types of 5.56 mm Ammunition in the U.S. Military
- Cartridge, 5.56mm, Ball, M193
- Cartridge, 5.56mm, Grenade, M195
- Cartridge, 5.56mm, Tracer, M196
- Cartridge, 5.56mm, High Pressure Test, M197
- Cartridge, Dummy, 5.56mm, M199
- Cartridge, 5.56mm, Blank, M200
- Cartridge, Dummy, 5.56mm, M232
- Cartridge, 5.56mm, Blank, M755
- Cartridge, 5.56mm, Ball, M855
- Cartridge, 5.56mm, Tracer, M856
- Cartridge, 5.56mm, Plastic, Practice, M862
- Cartridge, 5.56mm, Armor Piercing (AP), M995
Technical Specifications for the NATO SS109 5.56 Round
| Parameters | English/US | Metric |
|---|---|---|
| Bullet Weight | 62 gr | 4.01 gm |
| Bullet Type | Ball | |
| Muzzle Velocity at 78 feet (24 meters) |
2985 ft/sec | 910 m/sec |
| Muzzle Energy at 78 feet (24 meters) |
1224 ft-lbs | 1660 joules |
| Pressure: Maximum Average Maximum Average +3SD |
55000 PSI 61000 PSI |
3870 kg/cm2 4280 kg/cm2 |
| Accuracy SDX;SDY;MAX 3 X 30 rounds |
8.8" at 660 yards or 7.9" at 600 yards |
22.5 cm at 600 m or 20.0 cm at 550 m |
| Penetration | Complete penetration of SAE 1010/1020 steel plate, 3.5 mm thickness placed at a distance of 625 yards (570 meters) from the muzzle. |
|
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